Process for the production of an armoring component for motor vehicles

ABSTRACT

A process for the production of an armoring component for motor vehicles, the process beginning with provision of an armoring element made of an armored steel. At least one region of a surface of the armoring element is then subjected to particle-impact treatment. Finally, a coating is applied to the particle-impact-treated surface of the armoring element, where the coating consists of a material that is softer than the armored steel.

RELATED APPLICATIONS

The present application claims priority of German Application Number 10 2019 116 363.3 filed Jun. 17, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.

FIELD

The present disclosure relates to a process for the production of an armoring component for motor vehicles. Armored vehicles are intended to protect persons, and also material assets, from projectiles fired from weapons (ballistic protection). Such vehicles are intended to prevent penetration of projectiles from all directions. Construction of the vehicles therefore includes armoring components. Among these are lateral components inclusive of sills with A-, B-, C- and D-pillars and doors, front and rear components, roof region and floor assembly.

This ballistic resistance is achieved through use of armored steels with high toughness and hardness, and also by the geometric design of these, for example, an appropriate thickness of the components. The armoring components therefore have relatively high thickness, with correspondingly high weight. It is therefore desirable to reduce the weight of the components, but at the same time to ensure provision of the required ballistic resistance.

BACKGROUND

DE 10 2015 116 879 A1 discloses a vehicle-armoring component which comprises a coated steel sheet, where the coating consists of a material that is softer than the steel sheet. This permits reduction of the thickness of the steel sheet and thus of the weight of the component. In this component it is necessary that the bonding of the coating to the steel sheet is durably strong, for example, when subjected to multiple-hit ballistic impact does not break away or undergo any other form of separation.

SUMMARY

The disclosure was based on the above and addressed the problem of providing a process which can reliably produce an armoring component for motor vehicles that is durable and exhibits multiple-hit resistance.

DETAILED DESCRIPTION

The disclosure provides a process for the production of an armoring component for motor vehicles with the following steps:

-   -   provision of an armoring element made of an armored steel,     -   particle-impact treatment of at least one region of a surface of         the armoring element,     -   application of a coating to the particle-impact-treated surface         of the armoring element, where the coating consists of a         material softer than the armored steel.

The armoring component can be provided in a wide variety of forms. It is possible here to use not only cold-formed components but also hot-formed and press-hardened components.

In cases where the armoring components have been subjected to three-dimensional forming, their shape and geometry is thus appropriate to their use in the vehicle.

Their thickness can vary locally as required by their use. The thickness variation can be provided via machining or by treatment involving rolling techniques, or by the coherent bonding of two or more sheets of different thickness.

The thickness of the steel sheet of which the armoring element consists is between 5.0 millimeters and 10 millimeters, between 7.0 millimeters and 9.0 millimeters, or between 7.3 millimeters and 8.4 millimeters.

The particle-impact treatment is generally carried out on the surface that is directionally counterposed to the external side of the vehicle. The particle-impact treatment cleans and roughens the surface. It has been found that in the case of multiple-hit ballistic impact, i.e. multiple ballistic impact with small distance between the impact points, the effect achieved by the subsequently applied coating consists in retention of the coating and absence of separation and/or break-away of the coating from the armoring element, and therefore retention of ballistic resistance.

In an embodiment of the process, the particle-impact treatment uses a particle-impact material with hardness of 60 to 70 Rockwell (HRC), or 64 to 68 Rockwell (HRC). A particle-impact material of high hardness is necessary in order to achieve the necessary roughness depth in the armored steel. A particle-impact material made of cast steel is used.

During the particle-impact treatment, a particle-impact material has a diameter of 0.4 millimeter to 1.2 millimeters. A particle-impact material with this diameter produces finely dispersed surface undulations on the surface of the armoring element. Layer adhesion is thus additionally improved.

During the particle-impact treatment, the angle at which the particle-impact material impacts the surface, relative to said surface, is 30° to 70°. The angle of impact also affects the nature of the surface: any scale that may be present is thus removed in effective manner, while avoiding any unacceptable damage to the surface.

In a process embodiment, a surface roughness Ra of 3 to 10 micrometers is produced during the particle-impact treatment. It has been found that roughness as defined here ensures the ideal balance between adhesion of the coating on the surface and impairment of the surface itself. At smaller roughness depths, adhesion of the layer is significantly poorer; this leads to break-away of the layer over large areas during multiple-hit ballistic impact. Larger roughness depths can lead to distortion of the component when the sheet is particle-impact-treated only on one side.

A coating made of aluminum or of an aluminum alloy or of zinc or of a zinc alloy is applied.

The coating is applied by spraying, for example, by thermal spraying, by arc spraying or flame spraying. These processes permit production of a precise and variably configurable layer.

In another embodiment of the disclosure, the coating is applied in a plurality of layers, for example, in two or three layers. It has been found that a coating made of a plurality of layers has an effect on ballistic resistance.

Another embodiment of the disclosure provides that a coating is produced with thickness of 0.01 millimeter to 0.4 millimeter, 0.05 millimeter to 0.3 millimeter, 0.1 millimeter to 0.25 millimeter, or 0.12 millimeter to 0.22 millimeter.

An armoring element made of an armored steel made of a steel alloy is provided, and comprises at least the following alloy constituents expressed in percentage by weight (% by weight):

carbon (C) 0.2 to 0.5 manganese (Mn) 0.3 to 2.5 nickel (Ni) 0.5 to 3.0, and also further alloy constituents, the remainder being iron (Fe) and smelting-derived impurities.

The steel alloy comprises the following alloy constituents expressed in percentage by weight (% by weight):

silicon (Si) 0.1 to 3.0 phosphorus (P) less than 0.05 sulfur (S) less than 0.02 aluminum (Al) less than 0.08 copper (Cu) less than 0.12 molybdenum (Mb) 0.1 to 1.0 boron (B) 0.001 to 0.01 nitrogen (N) less than 0.05 chromium (Cr) 0.1 to 1.0 titanium (Ti) less than 0.1 cobalt (Co) less than 2.0 niobium (Nb) less than 0.8.

A steel alloy of this type is suitable for components according to the disclosure, because it exhibits low weight with high strength.

An armoring element made of a steel sheet with hardness 380 to 760 Vickers (HV), 475 to 665 Vickers (HV), or 520 to 620 Vickers (HV), is provided.

Ballistic resistance and, respectively, increased ability to withstand multiple ballistic impacts have been found when a coating with hardness of 10 to 230 Vickers (HV), 15 to 115 Vickers (HV), or 20 to 100 Vickers (HV), is provided.

The foregoing description of some embodiments of the disclosure has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed, and modifications and variations are possible in light of the above teachings. The specifically described embodiments explain the principles and practical applications to enable one ordinarily skilled in the art to utilize various embodiments and with various modifications as are suited to the particular use contemplated. It should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the disclosure. 

1-13. (canceled)
 14. A process of producing an armoring component for a motor vehicle, the process comprising: providing an armoring element comprising an armored steel, performing a particle-impact treatment on a region of a surface of the armoring element, applying a coating to the particle-impact-treated surface of the armoring element, the coating comprising a material softer than the armored steel.
 15. The process according to claim 14, wherein performing the particle-impact treatment uses a particle-impact material with a hardness of 60 to 70 Rockwell (HRC).
 16. The process according to claim 14, wherein performing the particle-impact treatment uses a particle-impact material with a diameter of 0.4 millimeter to 1.2 millimeters.
 17. The process according to claim 14, wherein performing the particle-impact treatment comprises particles impacting the surface at an angle ranging from 30° to 70° relative to the surface.
 18. The process according to claim 14, wherein performing the particle-impact treatment produces a surface roughness Ra of 3 to 10 micrometers.
 19. The process according to claim 14, wherein applying the coating comprising applying aluminum, an aluminum alloy, zinc, or a zinc alloy.
 20. The process according to claim 14, wherein applying the coating comprises spraying, thermal spraying, arc spraying, or flame spraying.
 21. The process according to claim 14, wherein applying the coating comprises applying a plurality of layers.
 22. The process according to claim 14, wherein applying the coating comprising applying the coating having a thickness of 0.01 millimeter to 0.4 millimeter.
 23. The process according to claim 14, wherein providing the armoring element comprises providing the armored steel comprising a steel alloy, the steel alloy comprising the following alloy constituents expressed in percentage by weight (% by weight): carbon (C) 0.2 to 0.5 manganese (Mn) 0.3 to 2.5 nickel (Ni) 0.5 to 3.0,

and also further alloy constituents, a remainder being iron (Fe) and smelting-derived impurities.
 24. The process according to claim 23, wherein providing the armoring element further comprises providing the steel alloy further comprises alloy constituents expressed in percentage by weight (% by weight): silicon (Si) 0.1 to 3.0 phosphorus (P) less than 0.05 sulfur (S) less than 0.02 aluminum (Al) less than 0.08 copper (Cu) less than 0.12 molybdenum (Mb) 0.1 to 1.0 boron (B) 0.001 to 0.01 nitrogen (N) less than 0.05 chromium (Cr) 0.1 to 1.0 titanium (Ti) less than 0.1 cobalt (Co) less than 2.0 niobium (Nb) less than 0.8.


25. The process according to claim 14, wherein providing the armoring element comprises providing a steel sheet with a hardness of 380 to 760 Vickers (HV).
 26. The process according to claim 14, wherein applying the coating comprises applying the coating having a hardness of 10 to 230 Vickers (HV).
 27. The process according to claim 14, wherein performing the particle-impact treatment uses a particle-impact material with a hardness of 64 to 68 Rockwell (HRC).
 28. The process according to claim 14, wherein applying the coating comprises applying the coating to a thickness of 0.1 millimeter to 0.25 millimeter.
 29. The process according to claim 14, wherein applying the coating comprises applying the coating to a thickness of 0.12 millimeter to 0.22 millimeter.
 30. The process according to claim 14, wherein providing the armoring element comprises providing a steel sheet with a hardness of 475 to 665 Vickers (HV).
 31. The process according to claim 14, wherein providing the armoring element comprises providing a steel sheet with a hardness of 520 to 620 Vickers (HV).
 32. The process according to claim 14, wherein applying the coating comprises applying the coating having a hardness of 15 to 115 Vickers (HV).
 33. The process according to claim 14, wherein applying the coating comprises applying the coating having a hardness of 20 to 100 Vickers (HV). 